Electromagnetronic valve apparatus



May 20, 1958 E. G. JOHNSON 2,835,353

ELECTROMAGNETRONIC VALVE APPARATUS Filed March 27, 1951 NVENTOR.

United States Patent ELECTROMAGNETRONIC VALVE APPARATUS Ervin G. Johnson, Oakland, Calif., assignor to Eleanor dc Haas Johnson, Oakland, Calif.

Application March 27, 1951, Serial No. 217,730

10 Claims. (Cl. 321--38) This invention relates to valving apparatus for changing alternating current to unidirectional current and has particular reference to a device for producing unidirectional currents of variable value and unidirectional currents which are reversible as to polarity, from alternating current.

It is one of the objects of my invention to produce direct current reversal of a variable output rectifier by the same device which produces the variable output.

Another object is to produce a voltage control device of continuously variable voltage output.

Other objects of the invention will be clear from the following drawings in which each of the various figures shows a wiring diagram and schematic layout of a different form of my invention, and in which drawings:

Figure 1 is a. showing of a full wave rectifier with output potential and polarity selective by a single control member.

Figure 2 is a modification of Figure 1- showing only a half wave rectifier with potential and polarity selective by a single control.

Figure 3 shows the invention used as a half wave variable impedance across the power source.

Figure 4 is a showing of the invention used as a half Wave variable impedance with series and/or shunt load.

Figure 1 The apparatus comprises a series of electronic valves Ilia, lllb 10h, which are identical in characteristics and which are respectively provided with anodes 11a, 11b 11h; cathodes 12a, 12b 1211, and control grid electrodes 13a, 13b 13h. These valves may be of the high vacuum or the gaseous conduction types, and if of the latter type, may be of the positive grid type.

The valves are grouped in pairs. Thus, valves 10a and 10s form pair lfiae; valves 10b and 10 form valve pair ltlbf; valves 10c and 10g form a third valve pair 100g; and valves llld and 1012 form a fourth valve pair 10ah. In each valve pair the cathode of one valve is coupled to the anode of the other valve in each case by connecting their anodes and cathodes together as shown. There are, accordingly, eight anode-cathode Illa-Me, l1e--l2a, 11;f12b, lib-12f, 11c-12g, 11g12c, lid-12k, and 11h-l2d.

Pairs of anode-couples are connected together as shown at m, n, and p to form four groups of two anodes and two cathodes. The anodes and cathodes in each group are, accordingly, at the same potential. The group pDC comprises the elements l1a12e11d12h; the group mAC comprises anodes 11e-11f and cathodes 12a and 12b; the anode cathode group nDC comprises cathodes 12f and 12g and anodes 11b and 110. The anode-cathode group oAC comprises cathodes 12c and 12d and anodes 11g and 11h.

The common terminals m and 0 respectively of anodecathode groups mAC and 0A0 are connected to a source of alternating current power AC; and the common ter- 2,835,863 Patented May 20, 1958 e CC initials p and n of anode-cathode groups nDC and pDC are connected to a unidirectional current consuming circuit up, which includes a unidirectional or direct current load.

The alternating current voltage applied to m and 0 is such as to require assisting biasing voltage to cause conduction in two valves in series. Thus, if it is supposed that m is positive and it is desired that current flow be only from n to p in the load, that is, that the terminal n be continuously positive with respect to terminal p, current flow is to be from m through valve 10 terminal n, D. C. load, terminal p, valve 10d, and then to the negative terminal 0. Valves 10d and 10f are tendered conducting by applying a voltage tending to assist flow of current in both of these tubes. As shown, the valves are equipped with the third electrodes, or control grids, to which assisting voltages are applied by apparatus and in a manner presently to be described. 7

While attaining a condition of current flow from m to o and including 11 to p, in the manner pointed out above,

current flow is prevented through all of the valves 10!),

10h, 10g, Ilia, ltla, and lite. As shown, valves 10b, i011, 10a and .Hlg are non-conducting because their cathodes 1211, 121:, 12a, and 12g are all respectively positive with respect to-their anodes ill), 11h, lla and Hg respectively. Valves ltle and the are non-conducting because they are, under the conditions stated, unprovided with assisting biasing voltage. In fact, as will be pointed out, the voltages on the control grids 13c and 130 are such as to actively prevent conduction in valves 102 and 100.

In a similar manner, when it is desired to have unidirectional current ilow from n to 2 while the terminal .0 is positive and m is negative, the current must flow along the path from 0, through valve 18g, terminal it, through the C. load to terminal 11, through valve 10a, thence to the negative terminal m. Under these conditions of current ilow only valves 16a and 10g are conducting.- Valves lfic, llid, Me, and lllf are non-conducting because of their cathode and anode voltages being positive when 0 is positive with respect to m; and valves 10/1 and 1% are non-conducting because both of lacking assisting voltage and of having a control grid bias which actually prevents current flow.

Current flow from n to 2 during both halves of the alternating current wave of voltage applied at m and 0 is accomplished by applying favorable control grid voltages to the grids of the valves as required. When in is positive, control grids 13f and 13d are forced positive in synchronism therewith by the voltage generated in the secondary windings 14 and 14d of the transformer 15. Transformer 1.? is excited from the supply source AC in parallel with terminals m and 0. Transformer 15 may be excited from a separate source of alternating current power which need not be in synchronism' with the source AC.

Transformer 15 comprises a core 15a and a primary winding 15b which under certain adjustment to be de scribed induces an alternating voltage in windings 14 and 14:1 in phase with the anode-cathode voltage in the valve llld, and the anode-cathode voltage in'the valve 10 The control grids 13d and 13] are, accordingly simultaneously forced positive, with the plates of the valves and each other, and current flows in these two valves during the half cycles while m is positive with 1-sspect to 0. During this half-cycle, valves lilo and-10s are, although their anode-cathode voltages are favorable -to conduct current, insutliciently-energized to d'o so. This is so because the control grids 13c and 13:; thereof are actually driven negative by the voltages induced in the transformer secondary windings 14c and 14a. Windings 14c and 14e have their terminals so chosen for connec.

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tion with the cathodes andcontrol grids that the anode to cathode voltage cannot produce conduction during this half of the cycle in these valves.

The other four valves are, of course, non-conducting because the cathodes thereof are positive with respect to the anodes.

During the portion of the voltage wave applying positive voltage from to m, valves a and 10g are rendered conductive by transformer secondary windings 14a and 14g which are wound on core a so that grids 13a and 13g run positive at the same time o is positive with respect to m. During this period valves 1% and 10h are non-conducting because the control electrodes or grids 13b and 13h are driven negative by the voltage generated in windings 14b and 14h. Valves 10e, 10 10c and 10d are non-conducting because their cathodes are positive with respect to their anodes.

When it is desired to reverse the flow of current in the D. C. load, so that p is positive and n negative thereto, the transformer 15 is adjusted so that the timing of conductivity of the valves is reversed. Under such conditions, when m is positive, current flow is from m through valve 10e to p, through D. C. load to n, through valve 10c and to terminal 0; and when m is negative the flow is via 0, valve 1011, p, D. C. load, n, valve 10b, and m. With m positive, grids Be and 13c are driven positive by the voltages induced in windings 14a and 140 by the flux in core 15a; and grids 131 and 13d are driven negative by the voltages induced in windings 14 and 14d so valves 10 and 10d are non-conducting when m is positive. Similarly, when m is negative, grids 13g and 13a are driven negative by voltages generated in coils 14g and 14a. While m is positive, valves 10a, 10b, 10g, and 10h are non-conducting because their cathodes are positive with respect to their anodes. While 0 is positive, valves 10c, 10d, 10 and 10e are non-conducting because their cathodes are positive with respect to their anodes.

The excitation of the core 15a by the primary windings 15 is reversible in respect to its phase relation to the voltage applied at m and 0. The winding 15b is divided into two sections S1 and S2 which are respectively nearly equal or equal in the numbers of their turns of wire about the core 15a. They are also about equal or equal in their impedances. They may be made as one continuous winding of all their turns going around the core in the same direction. A center tap is brought out at T1 from the mid-point of the winding. This tap is connected by conductor U1 to terminal 0 and to the source of alternating current at C. A potentiometer resistance:

R has its end terminals connected respectively to the end taps of primary winding 15b. The potentiometer slide contact V is connected by conductor U2 to terminal m and conductor A of the alternating current supply.

With voltage applied at V and T1, current divides at T1 and V flowing in parallel through sections S1 and S2 of the primary winding. When the parallel circuits between T1 and V are equal in impedance, the current is equal in the two sections S1 and S2. The windings S1 and S2 are wound so that when current flows in at T1 the flux force, or magnetomotive effects of the currents tend to balance each other. In other wards, the winding is continuous in the same direction, but the currents have opposing effects in the core. When the magnetomotive effects of S1 and S2 are equal, no flux is produced in core 15a. This condition is achieved for practical purposes by adjusting the position of slider V on potentiometer resistor R. I prefer to use a slide wire type resistor R for continuous resistance variations.

In order to produce substantial flux of any desired value in core 15a, slider V is adjusted to produce an unbalance of currents in S1 and S2. The resultant flux is dependent on the degree of unbalance; which is, in turn, produced in proportion to the ratio of the two portions of the resistance R, respectively r1 and r2, where r1 4 and r2 equals R, as determined by the position of slide contact V.

The flux produced in core 15a is determined, in efiect, by the excess of ampere turns in one section S1 over the ampere turns in the other section S2, or vice versa. The two currents being in phase, the magnetizations are always in a direction corresponding to the direction of current flowing in the winding producing the higher value of the product of current and turns carrying that current. Thus, when S1 carries more current than S2 their turns being equal, the fiux in core 15a is alternating in a certain phase relation with the voltage AC. This phase may be regarded as substantially in phase. However, if contact V is adjusted so that S2 carries more current than S1, then the phase of voltages 14a 14h is reversed with respect to their prior in-phase condition, and these voltages are then to be regarded as one hundred and eighty degrees out of phase. Such a reversal produces a reversal in the polarity relation between n and p, since it effects the control of the valves to allow current flow along the paths pointed out in the foregoing description.

The average amount of current through the D. C. load depends upon the average conductivity of the valves operating. This is determined by varying the degree of unbalance of magnetic force produced by the primary winding sections S1 and S2. Contactor V serves this purpose. It will be noted that the adjustment of R is continuously a change in ratio of resistances and not a stepwise change. For this reason the voltages delivered by the secondary windings 14a 14h are not stepped but continuous functions as to amplitude with respect to R and very precise secondary voltage control over a wide range is effected in this way.

It is to be observed also that the initiation and/or cutoff of current flow is very sharp and precise as to timing because the grid and the plate circuits both increase and decrease in voltage together.

It is also to be observed that the period in any half cycle for conduction is variable and always centered on the crest of the voltage wave applied to the plate circuit. It is also to be observed that, as respects any one valve, the assembly forms a variable passage for current in one half of the full cycle.

Inasmuch as but one moving contact is required to efiect the control functions the simplicity and long life of the device contributes to reliability. The use of the tubes facilitates rapid repair.

Figure 2 Figure 2 is a modification of Figure 1 which results in a half wave rectifier with output potential and polarity selective by a single control, whereas the showing of Figure 1 gives full wave rectification.

To obtain only half wave rectification, only two of the tubes 10 are needed. For this reason, the same reference characters are used in Figure 2 as in Figure l to indicate the same or similar parts of the circuits. The two tubes may be any of those shown in Figure 1 so long as they are oppositely poled as those shown 10g, 10c. The tubes may be on either side of the load or may be one on one side and one on the other side. Their grid control transformers 143, 14c are connected as shown and as set forth in connection with the description of Figure 1, and so arranged with respect to the center tapped transformer 15.

The potentiometer slide V has been shown to the left of center. This means that the left tube 10g will conduct and current will flow from a to m thru the load from n to p. If the slide V is moved 'to the right, then the right tube 10c will conduct and current will flow thru the load from p to n. The impedance value of the circuit is determined by the unbalance of the potentiometer, the distance of the slide V from center. Thus, as

in Figure 1, the direction and value of current flow in the load is determined by a single means, the position of the potentiometer slide V.

Figure 3 Figures 3 and 4 show the invention used as a variable half wave impedance. The reference characters used in these figures, where common with those of Figure 1, refer to the same or similar parts found in Figure 1. The potential on the grid 13 of the tube is determined by the position of the slide V of the potentiometer R connected across the center tapped transformer 15 which feeds the grid. In Figures 3 and 4-, this determines the conductance thru the tube 10; and, hence, in Figure 3, the impedance across the power line AC between the terminals 0, m of the tube 10.

Figure 4 In Fig. 4 the device functions as a variable series impedance in lines AC if load x is omitted, then producing a variable pulsating current on load Y. With load X, the alternations in X are equalized or unequalized in variable amounts in accordance with the position of V. Also the invention, as applied in Fig. 4, acts as a voltage regulator; when properly adjusted, an excess of voltage on load X causes the tube to conduct and therefore to reduce the current flow in load X during that half of the cycle. The other modifications may be similarly employed.

While I have shown and described specific embodiments of my invention, it will be apparent to those skilled in the art that changes and modifications can be made therein without departing from the true spirit of my invention or the scope of the accompanying claims in which, I claim:

1. In combination: a valve having an anode and a cathode and a grid, a source of alternating current, a transformer having electroconductively distinct primary and secondary inductively related windings with the primary winding having end and mid-point terminals; a potentiometer including a resistor having two end terminals, and including a slide contactor having a contact arranged for sliding over the resistor between the two end terminals thereof and having a slide contactor terminal; means electroconductively directly connecting the end terminals of the potentiometer resistor to the end terminals of the primary winding; means electroconductively connecting two points of diiferent voltage of the source of current respectively to the terminal of the slide contactor and the midpoint of the transformer primary winding; means connecting substantially the same points of the source of current to the anode and the cathode, and means connecting the secondary winding of the transformer to the cathode and grid.

2. A rectifier comprising, in combination: two terminals between which unidirectional current is to flow; a valve having an anode, a cathode, and a control electrode, and means connecting the anode to one of said two terminals and the cathode to the other of said two terminals; a transformer including a core and having a primary winding of two sections continuously wound in one direction around the core and a secondary winding wound on the core and means connecting one end of said secondary winding to the cathode of the valve and the other end of the secondary winding to the control electrode of the valve; a potentiometer resistance, means connecting one end of the potentiometer to one end of the primary winding and means connecting the other end of the potentiometer to the other end of the primary winding; an adjustable slide contactor contacting the potentiometer resistance between its ends; a source of alternating current; means for applying voltage from said alternating current source to a point between the ends of said primary winding and to the slide contactor between the ends of said potentiometer; and means for applying voltage from said alternating current source to the first mentioned two terminals.

3. A rectifier comprising, in combination: two terminals between which unidirectional current is to flow; two valves, each valve having an anode, a cathode, and a control electrode; conductor means connecting the anode of one valve and the cathode of the other valve together and to one of said two terminals, and conductor means connecting the cathode of the one valve and the anode of the other valve together and to the other of said two terminals; a transformer including a core and having a primary winding continuously wound in one direction around the core providing a tap at the midpoint in the primary winding into which current may flow and dividing the primary winding into two sections, and having two distinct secondary windings continuously wound around said core and each of said secondary windings having two output terminals which are respectively at any instant positive and negative with respect to each other; conductor means including a conductor joining, at any instant, an instantaneously positive terminal of one of said secondary windings to the control electrode of one of said valves and a second conductor joining the other terminal of said one secondary winding to the cathode of said one valve, and a third conductor joining the instantaneously negative terminal of said other secondary winding to the control electrode of the other valve and a fourth conductor joining the other terminal of said other secondary winding to the cathode of said other valve; a potentiometer resistance having one end thereof connected to one end of the primary winding and the other end thereof connected to the other end of the primary winding; a slide contactor having contact with the potentiometer between the ends thereof to divide the resistance into variable resistance sections one of which increases as the other decreases in resistance; a source of alternating current; a conductor connecting one side of the source of alternating current to the tap of said primary winding and a second conductor connecting the other side of the source of alternating current to the slide contactor; and means for applying voltage from the alternating source to the two first mentioned terminals.

4. An alternating to direct current rectifier system comprising, in combination: a first two terminals between which a unidirectional current is to flow; a second two terminals to which alternating current is to be applied; four groups of valves, each group of valves including two valves and each valve including an anode, a cathode, and a control grid and, in each group, the cathode of one valve being conductively joined to the anode of the other valve to form a first anode-cathode couple, and the anode of the one valve being joined to the cathode of the other valve to form a second anode-cathode couple; a first conductor means joining the first anode-cathode couples of two groups to one of the alternating current terminals, a second conductor means joining the second anode-cathode couple of one of said two groups to one of the first two terminals, a third conductor means joining the second anode-cathode couple of the other of said two groups to the other of the first two terminals, a fourth conductor means joining two first anode-cathode couples of the other two groups of valves to the other alternating current terminal, a fifth conductor means joining the second anode-cathode couple of one of the last mentioned two groups of valves to one of said first two terminals, and a sixth conductor means joining the other anode-cathode couple of the second of the last mentioned two groups of valves to the other of said first two terminals; a transformer having a primary winding and having a potentiometer connected across the terminals of the primary winding, a source of alternating current connected to the primary winding near its mid-turn and to the potentiometer to divide the resistance thereof between the resulting two sections of the primary winding, and said transformer having four secondary windings, each secondary winding having a mid-tap joined to one of the first four mentioned terminals and an end terminal of the resulting sections joined to the control electrode of one of the valves; and means for varying the resistances in the primary winding sections.

5. A device for rectifying alternating current and including means to reverse the output polarity of the unidirectional current of the device comprising, in combination: a pair of three electrode electronic valves each including anode, cathode, and grid; means connecting the anode and cathode of the respective valves together and to one terminal of a source of alternating current; means connecting the other cathode and anode of the valves together and to one terminal of a load circuit; terminal means connected to the other terminal of the source of supply and to a second terminal of the load circuit; a transformer having a primary Winding and secondary windings; means connecting respective ones of the secondary windings to control the grids of the valves and to render one conductive and the other non-conductive at selected times; a potentiometer resistance connected across the end terminals of the primary winding; a slide contactor for the potentiometer and a center tap on the primary winding; and means connecting the source of alternating current to the slide contactor and the center tap to cause flow of current therethrough.

6. In combination: at least two valves having anodes and cathodes, means connecting the anode of one of the valves to the cathode of another and the cathode of the one to the anode of the other, a source of alternating current, and alternating current means for connection in circuit with and responsive to the alternating current connected with the valves for simultaneously rendering one conductive and the other non-conductive and means for simultaneously adjusting the said alternating current means for rendering the one non-conductive and the other conductive.

7. in a rectifier having at least two valves, each valve comprising an anode, a cathode, and a control electrode, and of which two valves the anode and cathode of one are directly connected respectively to the cathode and anode of the other; and means comprising a single source of alternating current connected to both cathodes and control electrodes for causing either one or the other of said valves to become conducting of alternating current half cycles applied from said source to said valves.

8. A rectifier system comprising, in combination: two valves each having an anode and a cathode; separate terbranches and each branch including part of said primary winding and part of said impedance in series circuit relation; means for varying the ratio of the impedance part in one branch with respect to the impedance part in the other branch; means including the varying means for connecting coterminal ends of the respective branches directly to two points of different voltage in a source of alternating current; said transformer including two secondary windings; and means applying the voltages generated in the secondary windings to respectively assist and impede the voltage applied to the anode and cathode of the respective valves so as to control current flow through said valves.

9. A transformer according to claim 8, said winding sections being wound and connected to the same source of current so that their 'magnetomotive efiects are opposed.

10. In a rectifier having at least two valves, each valve comprising an anode, a cathode, and a control electrode, and of which two valves the anode and cathode of one are directly connected respectively to the cathode and anode of the other; means for causing one or the other of said valves to become conducting during each of a continuous series of alternating current pulsations applied to the anode and cathode while the other of said valves remains non-conducting during said same series of pulsations; and means for causing the other of said valves to become conducting during each of another series of pulsations similarly applied while the one valve remains non-conducting during such other series of pulsations; said last named two means comprising a transformer having a primary Winding and a secondary Winding; and further comprising: a slide wire resistor having its ends connected across the terminals of the primary winding,

. a source of alternating current, and means connecting the minal means connecting the anode of each valve to the cathode of the other valve; means for connecting a source of alternating current to said terminal means; a transformer having a primary winding and an impedance connected in continuous closed circuit with the primary winding there being two separated coterminal means in said closed circuit constituting thereof parallel circuit alternating current between the ends of the resistor and between the ends of the primary winding, and means connecting the secondary winding to assist or resist flow of current in the valve circuits.

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